EP0506995A1 - Alliage utilisable pour systèmes d'adduction d'eau et présentant des propriétés améliorées pour l'usinabilité et la mise en forme - Google Patents

Alliage utilisable pour systèmes d'adduction d'eau et présentant des propriétés améliorées pour l'usinabilité et la mise en forme Download PDF

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Publication number
EP0506995A1
EP0506995A1 EP91108359A EP91108359A EP0506995A1 EP 0506995 A1 EP0506995 A1 EP 0506995A1 EP 91108359 A EP91108359 A EP 91108359A EP 91108359 A EP91108359 A EP 91108359A EP 0506995 A1 EP0506995 A1 EP 0506995A1
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Prior art keywords
lead
alloy
weight
water
rest
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Application number
EP91108359A
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German (de)
English (en)
Inventor
Kenkichi c/o Toyo Brass Co. Ltd. Yamaji
Rokuro c/o Toyo Brass Co. Ltd. Kawanishi
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TOYO BRASS CO Ltd
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TOYO BRASS CO Ltd
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Publication of EP0506995A1 publication Critical patent/EP0506995A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/04—Alloys based on copper with zinc as the next major constituent

Definitions

  • the present invention relates to an alloy suited for use in water service, particularly to an alloy having less tendency for lead to dissolve in water, free cutting property and freedom from gravity segregation in casting and cracks caused by forming.
  • Lead-bearing brass a Cu-Zn-Pb ternary alloy
  • the lead content of the alloy is adjusted taking accout of cutting properties required.
  • four kinds of free-cutting brass are defined in Japanese Industrial Standards.
  • a lead content of 3.0 to 3.5 weight % is said to be most effective to obtain free cutting property.
  • These Cu- Zn-Pb ternary alloys are mainly used for livelihood devices and tools, especially for materials coming into contact with water, such as in devices for water supply.
  • Lead-bearing brass allows lead to dissolve into water in contact with the alloy used in tap devices. Such lead dissolution must be taken into account from the view point of environmental hygene.
  • the progress in water source development leads to a greater variety in quality of tap water. Further, hot water is used more widely as the hot water equipments are more and more popular. Therefore, the quality and the temperature of water must be taken into account in connection with lead dissolution.
  • Such fracture may be attributed to the distribution state of lead deposited in grain boundaries (or sub-grain boundaries) in the solidified alloy because lead does not form a solid solution with either copper or zinc. Free cutting property is also impaired remarkably by a hot process such as hot extrusion and heat annealing due to coagulation of lead particles during the heating.
  • an object of the invention is to provide an alloy having less tendency for lead to dissolve in water in no relation to the quality and the temperature of water and free from gravity segregation and uneven distribution of lead within an ingot in casting and from cracks caused by cold working.
  • a further object of the invention is to provide an alloy having improved free cutting property.
  • a still further object of the invention is to provide an alloy free from fructuring caused by hot forging.
  • an alloy comprises 57 to 61 weight % of copper, 0.5 to 3.5 weight % of lead, at least one metal selected from rare earth metals in an amount of 1/17 to 1/5 relative to lead in weight and zinc for the rest.
  • an alloy comprises 57 to 61 weight % of copper, at least 0.5 weight % but less than 3.0 weight % of lead, at least one metal selected from rare earth metals in an amount of 1/17 to 1/5 relative to lead in weight and zinc for the rest.
  • the alloy according to the invention contains 0.5 to 3.0 weight % of lead in order to achieve less tendency for lead to dissolve in water in no relation to the quality and the temperature of water.
  • An alloy containing at least 0. 5 weight % but less than 3.0 % of lead is preferable to prevent fructuring caused by hot forging.
  • the lead content greater than 0.5 % but at most 2.0 % is more preferred to prevent fructuring by hot forging.
  • rare earth metals lanthanum, cerium, praseodymium and neodium are preferable. So called Misch metal containing these metals may be used.
  • Rare earth metals in the alloy according to the invention form intermetallic compounds with any of copper, zinc and lead, of which those formed with lead have melting points higher than those formed with copper or zinc, indicating greater thermal stability of the compounds.
  • Some examples are shown in Table 1. It is supposed that intermetallic compounds of rare earth metals with lead are formed more readily than those with copper or zinc, such intermetallic compounds formed serve as crystal nuclei to form crystals more finely dispersed and make the dispersed phase as a whole more uniform and fine, and thus, either cold working or hot forging does not case cracks or fructure due to the deposition of lead in grain boundaries which is observed in conventional Cu-Zn-Pb alloys.
  • Table 1 Composition of intermetallic compound Melting point (°C) Chemical formula Weight ratio of rare earth metal CeCu6 26.88(%) 940 CeCu4 35.54 780 CeCu2 52.44 820 CeCu 68.80 515 LaCu4 35.34 902 LaCu3 42.16 793 LaCu2 52.23 834 LaCu 68.62 551 CeZn11 16.31 785 CeZn7 19.23 972 CeZn5 30.00 870 LaZn6 20.00 974 LaZn4 35.00 872 LaZn2 51.59 855 LaZn 68.00 815 CePb3 18.40 1170 Ce2 Pb 57.49 1380 LaPb3 18.37 1030 LaPb 40.14 1246 La2 Pb 57.28 1315
  • intermetallic compounds formed by the rare earth metals added to a Cu-Zn-Pb alloy lead to a reduced number and amount of free Pb phase formed in the alloy, some of which may be present locally in the particles attached to those of intermetallic compounds to form composite particles, resulting in reduced amount of lead dissolved in water.
  • Two preferred embodiments of this invention are alloys of the composition indicated in Table 2.
  • R. E. in the table denotes Misch metal.
  • Table 2 Examples Chemical composition (wt.%) Cu Pb R.E Zn R.E./Zn 1 59.5 3.0 0.60 rest 1/5 2 60.0 2.0 0.133 rest 1/15
  • the alloys are produced by the following procedure. Brass consisting of 60 weight % of copper and 40 weight % of zinc is melted in air, a predetermined amount of lead and Misch metal (R. E.) is added to the melt, the melt is casted in a mold of Isolite refractory to form an alloy ingot, which is cold-worked to permit reduction of 15 % to form a round rod of 10 mm in diameter, heated at 700°C for 1 hour or 3 hours, respective to each sample, and air-cooled at last. Metallographic observation was made with a cross-section of the round rod.
  • Figs.1A, 1B and 1C show microscopic metallographs of alloys of Example 1 without heating, after heating for 1 hour and 3 hours at 700°C, respectively.
  • Figs.2A, 2B and 2C show microscopic metallographs of alloys of Example 2 without heating, after heating for 1 hour and 3 hours at 700°C, respectively.
  • very finely dispersed particles are observed which appears to consist of lead or intermetallic compound are dispersed very finely. The dispersion is found to be still fine after heating, though the grains have grown slightly by heat treatment.
  • the alloys of Example 1 are less susceptive to heat than that of Example 2 with respect to metallographic structure.
  • Figs. 3A, 3 B and 3C show microscopic metallographs of the conventional lead-bearing brass for comparison without heating, after heating for 1 hour and 3 hours at 700°C , respectively.
  • the grains have grown in the couse of heating, and also the particles of lead are coagulated in grain boundaries.
  • An alloy C-2 containing Cu, Zn, Pb and less amount of Misch metal and a lead-bearing brass C-3 were prepared for comparison. Their compositions are shown in Table 5 (R.E. denotes Misch metal). Microscopic metallographs of these alloys are shown in Fig.4B and Fig.4C. Table 5 Alloy Chemical composition (wt.%) Cu Pb R.E Zn R.E./Zn C-2 58.8 2.2 0.10 rest 1/22 C-3 59.0 2.1 0 rest 0
  • the dispersed phase is more fine in comparison to that of alloy C-2 containing less amount of Misch metal shown in Fig.5B.
  • the results of X-ray microanalysis in Table 7 indicate that an intermetallic compound of definite composition is formed in dispersed state in the alloy of this invention, whereas no intermetallic compound is formed in some of the dispersed particles (see Particle f) in alloy C-2 containing less amount of Misch metal, or otherwise, even if intermetallic compound is formed, it is confined to the central part of the particle (see Particles d and e).
  • the intermetallic compound formed in the alloy of Example 3 is estimated to be CePb3 , taking account of the accuracy of analysis.
  • Alloys of compositions shown in Table 8 were prepared and formed into round rods for lead dissolution tests. Alloys 2 to 4 and 6 to 8 are the alloys according to the invention, while alloys 1 and 5 are conventional lead-bearing brass without rare earth metals. Table 8 Alloy No. Chemical composition (wt.%) Cu Pb R.E. Zn M.M./Pb 1 59.5 1.0 - rest - 2 59.5 1.0 0.07 rest 1/14 3 59.5 1.0 0.10 rest 1/10 4 59.5 1.0 0.20 rest 1/5 5 59.5 3.0 - rest - 6 59.5 3.0 0.20 rest 1/15 7 59.5 3.0 0.30 rest 1/10 8 59.5 3.0 0.60 rest 1/5
  • each alloy was prepared by the following procedure. Brass consisting of 60 weight % of copper and 40 weight % of zinc was melted by low frequency induction furnace; a predetermined amount of lead and Misch metal (R.E.) was added to the melt; the melt was casted semi-continuously in a vertical mold to form an ingot of 115mm in diameter; and the ingot was hot extruded to form a round rod of 28 mm in diameter and reduced in diameter to 25 mm by cold drawing and annealed.
  • R.E. lead and Misch metal
  • the specimen thus prepared were cut by turning to form a rod of 20 mm in diameter. Cutting was carried out at a speed of 2000 rotations per minute and a feed rate of 0.1 mm per rotation, making use of a bite of tungsten carbide, the shape of which is shown in Fig.6A.
  • the bite 61 includes shank 62, rake 63 having front edge 64 and side edge 65, front relief 66 and side relief 67. Cutting was carried out in the manner shown in Fig.6B.
  • Bite 61 cuts the rod of alloy 68 rotated in the direction shown by the arrow at its front and side edges (see Fig. 6A), producing chip 69 of the alloy.
  • Fig.8 The results for samples 1 and 4 immersed in water B are shown in Fig.8 in which the concentration of lead in water is plotted as a function of time, while Fig. 9 shows the results for samples 5 and 8 immersed in water B.
  • Fig. 10 shows the relation between the concentration of lead in the water after immersion for 72 hours at the temperature of 23°C and Misch metal content in the alloy of samples 1 to 4 (containing 1 % of lead).
  • Fig.11 shows such relation at the temperature of 72°C
  • Fig. 12 and 13 show such relation for samples 5 to 8 (containing 3 % of lead) immersed in water B at 23°C and 72°C, respectively.
  • Fig.8 and Fig.9 indicate that the concentration of lead in the water reaches a saturation after 24 or 48 hours, and the lead dissolution are greater for the alloy containing 3 % of lead than that containing 1 % and for the higher temperature. It his indicated that the addition of Misch metal inhibits lead from dissolution into water at 72°C, more effectively for the alloy containing 3 % of lead compared to that containing 1 %, though the effect is obscure for water at 23°C.
  • Figs.8 to 13 indicate that the concentration of lead dissolved in water tends to decrease with the greater amount of Misch metal (at most 1/5 to lead) added to the alloy. This tendency is more remarkable for elevated water temperature and for the higher lead content of 3% compared to that of 1%.
  • the concentration of lead dissolved in water depends on the kind of water, being less for water B, higher for water C. This dependency may be attributed, at least partly, to the conductivity of water which is lower for water B, higher for water C.
  • alloys 11 to 14 and 16 to 18 are the alloys according to the invention, while alloys 20 to 22 are similar alloys which contain 3 weight % of lead.
  • the sample of each alloy for hot forging tests was prepared by the following procedure. Brass consisting of 60 weight % of copper and 40 weight % of zinc was melted by low frequency induction furnace; a predetermined amount of lead and Misch metal (R.E.) was added to the melt; the melt was casted semi-continuously in a vertical mold to form an ingot of 115 mm in diameter, the ingot was hot-extruded to form a round rod of 28 mm in diameter and reduced in diameter by cold drawing to 25 mm, annealed and cut into pieces of 35 mm in length. Hot forging was carried out in a manufacturing line at a temperature of 690°C to 720°C. Table 10 Alloy No. Chemical composition (wt.%) Cu Pb R.E.
  • Alloys of compositions shown in Table 12 were prepared (R.E. denotes Misch metal) and formed into round rods for machinability tests. Alloys 33 and 34 are conventional lead-bearing brass without rare earth metals, alloys 31 and 32 are the alloys according to the invention, while alloys 35 and 36 are similar alloys which contain 3 weight % of lead. Table 12 Alloy Chemical composition (wt.%) Cu Pb R.E.
  • Alloys were prepared in the same manner as in Example 3.
  • the specimen for machinability test of each alloy was prepared by the following procedure. An ingot of 30 mm in diameter was hot-extruded to form a round rod of 7.5 mm in diameter, reduced in diameter by cold drawing to 6.5 mm, annealed and subjected to cold-drawing again so that a round rod of 6.0 mm in diameter was prepared.
  • the specimen of the alloy of Example 1 and alloy C-1 described before were also prepared in the same manner.
  • Cutting was carried out at a speed of 2000 revolutions per minute and a feed rate of 0.1 mm per revolution, to the depth of cut of 1.0 or 1.5 mm, making use of a bite of tungsten carbide as shown in Fig.6A and Fig.6B.
  • the length and curling diameter of the chips produced in cutting were measured.
  • the results are shown in Table 13, where the chip lengths are classified into four classes, of which 'SS' represents a length not more than 3 mm, 'S' represents 3 to 10 mm, 'SL' represents 10 to 40 mm, and 'L' represents 40 to 120 mm. Curling diameters are classified into 's' representing smaller than 3 mm, 'm' representing 3 to 10 mm, and 'l' representing greater than 10 mm.
  • alloys of this invention as well as alloy 35 have free cutting property, equal or superior to conventional lead-bearing brass (alloys 33 and 34). But alloy 36 containing Misch metal in the weight ratio of 1/5 to lead is degraded in free cutting property.
  • the restraining of lead from dissolving out into water may be attributed to the formation of intermetallic compounds of lead with rare earth metals which inhibits the dispersed phase consisting of free lead from forming and may serve to combine free lead. if it is present, at least partly.
  • the freedom from fructure in hot forging of the alloy of this invention containing at least 0. 5 weight % but less than 3.0 weight % of lead may be attributed to the comparatively fine dispersion of lead-bearing phase by the addition of a rare eath metal.
  • the alloy according to the invention has less tendency for lead to dissolve into water in no relation to the quality and the temperature of water, and is free from gravity segregation and uneven distribution of lead within an ingot in casting and from cracks caused by cold and hot working.
  • the alloy according to the invention has improved free cutting property.
  • the alloy of the invention is suited for use in devices for water service, such as tap water supply, taking advantage of less tendency for lead to dissolve into water, in no relation to the quality and the temperature of water.
  • the alloy according to the invention containing at least 0.5 weight % but less than 3.0 weight % of lead is free from fructure and cracks caused by hot forging.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Forging (AREA)
  • Domestic Plumbing Installations (AREA)
  • Sliding-Contact Bearings (AREA)
EP91108359A 1991-03-30 1991-05-23 Alliage utilisable pour systèmes d'adduction d'eau et présentant des propriétés améliorées pour l'usinabilité et la mise en forme Withdrawn EP0506995A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP93493/90 1991-03-30
JP09349391A JP3399548B2 (ja) 1991-03-30 1991-03-30 熱間鍛造用合金

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EP0506995A1 true EP0506995A1 (fr) 1992-10-07

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US (1) US5262124A (fr)
EP (1) EP0506995A1 (fr)
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0711843A2 (fr) 1994-10-28 1996-05-15 Wieland-Werke Ag Utilisation d'un alliage de cuivre-zinc pour installations d'eau potable
DE10158130C1 (de) * 2001-11-27 2003-04-24 Rehau Ag & Co Verwendung einer korrosionsbeständigen Kupfer-Zink-Legierung für Trinkwasserformteile
DE10301552B3 (de) * 2003-01-16 2004-06-24 Rehau Ag + Co. Korrosionsbeständige Messinglegierung für Trinkwasserformteile

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5637160A (en) * 1991-03-01 1997-06-10 Olin Corporation Corrosion-resistant bismuth brass
US5544859A (en) * 1994-06-03 1996-08-13 Hazen Research, Inc. Apparatus and method for inhibiting the leaching of lead in water
JP4190260B2 (ja) * 2001-12-12 2008-12-03 日本パーカライジング株式会社 鉛含有銅合金の表面処理方法及びその銅合金製接水部材
CN102676874A (zh) * 2012-06-12 2012-09-19 洛阳汇工大型轴承制造有限公司 一种镧铜轴承保持架的材料和铸造工艺方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT192124B (de) * 1954-07-09 1957-09-25 Goldschmidt Ag Th Kupferlegierungen für Lagerzwecke, Armaturen, Apparate für die chemische und Elektro-Industrie sowie Verfahren zu ihrer Herstellung
GB1007164A (en) * 1961-05-08 1965-10-13 Chase Brass & Copper Co Copper base alloys and a method of treating them to improve their machinability
GB1193201A (en) * 1967-02-28 1970-05-28 Imp Metal Ind Kynoch Ltd Copper-Base Alloys
SU492578A1 (ru) * 1974-02-19 1975-11-25 Казахский политехнический институт им.В.И.Ленина Сплав на основе меди
GB2211206A (en) * 1987-10-16 1989-06-28 Imi Yorkshire Fittings Casting alloy

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD132196A1 (de) * 1977-06-20 1978-09-06 Klaus Kirchberg Kupfer-zink-legierung mit geringer gratbildung und verfahren zur erzielung dieser eigenschaft

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT192124B (de) * 1954-07-09 1957-09-25 Goldschmidt Ag Th Kupferlegierungen für Lagerzwecke, Armaturen, Apparate für die chemische und Elektro-Industrie sowie Verfahren zu ihrer Herstellung
GB1007164A (en) * 1961-05-08 1965-10-13 Chase Brass & Copper Co Copper base alloys and a method of treating them to improve their machinability
GB1193201A (en) * 1967-02-28 1970-05-28 Imp Metal Ind Kynoch Ltd Copper-Base Alloys
SU492578A1 (ru) * 1974-02-19 1975-11-25 Казахский политехнический институт им.В.И.Ленина Сплав на основе меди
GB2211206A (en) * 1987-10-16 1989-06-28 Imi Yorkshire Fittings Casting alloy

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0711843A2 (fr) 1994-10-28 1996-05-15 Wieland-Werke Ag Utilisation d'un alliage de cuivre-zinc pour installations d'eau potable
US5766377A (en) * 1994-10-28 1998-06-16 Wieland-Werke Ag Copper-zinc-alloy for use in drinking-water installations
DE10158130C1 (de) * 2001-11-27 2003-04-24 Rehau Ag & Co Verwendung einer korrosionsbeständigen Kupfer-Zink-Legierung für Trinkwasserformteile
WO2003046237A1 (fr) * 2001-11-27 2003-06-05 Rehau Ag + Co Utilisation d'un alliage cuivre-zinc resistant a la corrosion pour produire des pieces façonnees destinees au domaine de l'eau potable
DE10301552B3 (de) * 2003-01-16 2004-06-24 Rehau Ag + Co. Korrosionsbeständige Messinglegierung für Trinkwasserformteile
EP1439238A1 (fr) 2003-01-16 2004-07-21 REHAU AG + Co Alliage de laiton résistant à la corrosion pour pièces en contact avec l'eau potable

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US5262124A (en) 1993-11-16
JPH0543965A (ja) 1993-02-23
JP3399548B2 (ja) 2003-04-21

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